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添加剂作用下铝酸钠溶液物化性质的变化对产品性能的影响 总被引:2,自引:0,他引:2
在铝酸钠溶液的晶种分解过程中,加入适当的添加剂--表面活性剂,可以强化铝酸钠溶液的晶种分解过程,提高产品氢氧化铝的强度、粒度和分解率.选用8种添加剂,100mg/L和200mg/L两种添加量做分解试验,对加入不同类型添加剂的铝酸钠溶液的表面张力、粘度、电导率进行了测试,考察了添加剂的加入量对铝酸钠溶液物理化学性质的影响.结果表明:添加剂C、E2、F可以提高铝酸钠溶液的分解率,并能增大产品氢氧化铝的粒度与强度;添加剂的加入使铝酸钠溶液的表面张力降低0.015~0.020N/m时,析出的氢氧化铝的粒度与强度较好;能使氢氧化铝粒度增大、强度提高的添加剂,均使铝酸钠溶液的粘度有所下降. 相似文献
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添加剂强化铝酸钠溶液分解的实验研究 总被引:2,自引:0,他引:2
研究了结晶添加剂对铝酸钠溶液加种分解过程中的二次成核,附聚的影响。并把添加剂应用于工业铝酸钠溶液种分实验过程中,探讨其对产品氢氧化铝粒度,产率的影响。结果表明:结晶添加剂能减少种分溶液中细粒子数,加强附聚作用的进行,粗化产品的粒度,提高产率。 相似文献
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拜耳法生产氧化铝是目前最为经济应用最为广泛的生产工艺,有多个生产环节构成其中尤以溶出和分解两道工序为重点工序,矿浆在溶出工序制备为铝酸钠溶液,又在分解工序析出其中的氢氧化铝,因而分解工序对最终氧化铝的粒度、质量有很大影响,本结合分解工序的调整控制介绍了析出氢氧化铝粒度的相关工艺和控制措施。 相似文献
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研究了磷酸盐杂质对铝酸钠溶液晶种分解的影响,并探讨了其影响机理.结果表明,在浓度小于5g/L时,磷酸盐能提高铝酸钠溶液的分解率,使晶种分解产品的粒度增大.磷酸盐杂质的存在不会显著影响铝酸钠溶液中氢氧化铝颗粒表面的Zeta电位值,但是会使铝酸钠溶液表面张力增大. 相似文献
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影响拜年法种分过程氢氧化铝粒度的因素很多,控制好分解过程的条件对产出率和产品质量都有很大影响.铝酸钠溶液的分解是在多组分体系内进行的,要获得一定粒度和强度的氧化铝。必须综合考虑种分过程对各种技术条件的控制。 相似文献
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在一定工艺条件下,研究了添加剂1,2-辛二醇对铝酸钠溶液种分产品强度和形貌的影响。结果表明,添加剂1,2-辛二醇的加入能明显抑制铝酸钠溶液的分解(分解初期),同时加入添加剂后铝酸钠溶液种分生成了很多小晶体,这些小晶体或填充在晶粒缺口处;或镶嵌成大颗粒,且大颗粒之间有充当粘结剂的更细的晶粒填充,明显改善了产品的强度。 相似文献
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选用核糖作为铝酸钠溶液种分过程的添加剂,在αk=1.40、温度75℃、搅拌速度140 r/min、晶种添加量为80 g/L条件下,研究不同添加量和不同苛碱浓度下铝酸钠溶液种分分解率及产品粒度的变化,结果表明:当添加量为150 mg/L、苛碱浓度为160 g/L时,核糖对种分过程的抑制作用最大。随着核糖添加量的增大,产品氢氧化铝粒度减小,但是核糖的添加并不能完全抑制氢氧化铝的附聚。核糖的加入改变了种分过程,且随着苛碱浓度的增大,种分过程出现成核现象,成核现象持续的时间也越长。 相似文献
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The effect of mannitol and 1,2-octanediol on gibbsite crystallization from seeded sodium aluminate liquor was investigated and compared. The inhibitory effect of mannitol increases with its concentration, in good agreement with other strong inhibitors. Low concentrations of 1,2-octanediol have no apparent influence on crystallization but above 1.0 mmol/L severe inhibition occurs with crystallization rate rapidly decreasing until completely stopped 2.0 mmol/L. Unlike with mannitol, the inhibition cannot be alleviated by doubling the seed amount or by adding oleic acid. Unseeded experiments also show that a high concentration of 1,2-octanediol inhibits Al(OH)3 nucleation while the influence of low concentration of 1,2-octanediol is negligible. 1,2-octanediol appears to be a unique inhibitor for alumina crystallization. The effect is evident below the critical micelle concentration of 1,2-octanediol in sodium aluminate solution indicating it is a molecular effect. Infrared spectroscopy indicates that the structure of the solution might be changed when the concentration of 1,2-octanediol is relatively high. Clearly the inhibition by mannitol derives from adsorption on the active surface sites, while inhibition by 1,2-octanediol appears to be due to changing the characteristic of sodium aluminate liquor. 相似文献
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《Hydrometallurgy》2007,89(1-4):121-126
In Bayer process gibbsite (alumina trihydrate, Al2O3·3H2O) is precipitated from sodium aluminate liquor for production of alumina by calcination. Precipitation of boehmite or alumina monohydrate (Al2O3·H2O) is an alternative method for production of alumina. Boehmite is also a good precursor material for production of different activated aluminas. At present this boehmite precipitation process is in the early stage of development. This process if developed would reduce the energy consumption for making alumina. The present work is aimed to carry out boehmite precipitation under atmospheric pressure conditions. Parameters such as alumina/caustic (A/C) ratio and temperature are varied to precipitate out boehmite from synthetically prepared sodium aluminate liquor. It was found that boehmite precipitation could be possible at normal pressure only when boehmite seed was added to the supersaturated sodium aluminate solution keeping the alumina/caustic ratio at either 1.1 or 1.0 and temperature at ≥ 85 °C. By decreasing the A/C ratio to 0.95 and below, it was possible to precipitate out boehmite at 60 °C. 相似文献
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A new process to produce monosodium aluminate hydrates (MAH) by fast crystallization from the leach liquor of a diasporic bauxite in concentrated NaOH solution is presented. The crystallization of MAH was carried out easily compared to the precipitation of gibbsite and the effect of agitation, initial concentration of sodium aluminate, seed amount and the presence of red mud were systematically studied in a batch crystallizer. The apparent kinetics of crystallization followed a second order rate law with an apparent activation energy for MAH crystallization of 38.0 kJ/mol which implies a surface-diffusion controlled mechanism. X-Ray diffraction and scanning electron microscopy identified the structure of MAH as Na2O·Al2O3·2.5H2O with a flake crystal morphology. The molar ratio α of Na2O to Al2O3 in the MAH products was < 1.2 after a simple wash by dilute sodium aluminate. 相似文献
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研究了1,2-辛二醇对铝酸钠溶液种分过程的影响。结果表明,1,2-辛二醇对铝酸钠溶液种分过程产生抑制作用。1,2-辛二醇的添加浓度、实验温度以及苛碱浓度等因素对1,2-辛二醇改善铝酸钠溶液种分效果具有显著影响。添加浓度小于1.25 mmol/L时,1,2-辛二醇对铝酸钠溶液的抑制程度很小,产品氢氧化铝的粒度分布基本维持与未添加时一致;添加浓度超过1.5 mmol/L,抑制作用非常明显,产品氢氧化铝粒度曲线主峰明显左移,平均粒度减小。温度越低,苛碱浓度越大,1,2-辛二醇对铝酸钠溶液分解抑制作用越大,产品氢氧化铝的细化程度越大。X射线衍射(XRD)显示,加入1,2-辛二醇后种分产品的晶型不变。 相似文献
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试验研究了苯甲酸钠、草酸钠、柠檬酸钠和酒石酸钠四种中低分子量的有机物对铝酸钠溶液(CNa2O=150 g/L,αk =1.45)粘度的影响.研究结果表明,随着有机物浓度从0升高到0.7 g/L,铝酸钠溶液的粘度逐渐降低,主要因为有机阴离子的加入抑制Al(OH)4-向聚合铝酸根离子的转变,降低了溶液的内摩擦力,从而降低了... 相似文献